How do you rate books?

Every time I rate a book, I struggle with what I’m rating it on.

Both Amazon and GoodReads use a 5 star system. If I loved the book, that’s easy. However, what if I liked the book except for the ridiculous stereotypical romance that was a minor theme. Do I ding it half a star? What if I read a romance and it’s really well written and the character development is good but I hate romances? Do I rate it on how good of a romance it is? (Maybe pretty good.) Or on how well I liked it?(Maybe not at all.)

And it depends on who I’m rating it for: me, friends, potential readers or authors. If these ratings are just for me, maybe to remember how I like a book or for some system to recommend books for me, then it’s simpler. I’ll rate it based on much I liked it overall. But these ratings are also for our friends to see if books are good. And if you leave your rating on Amazon, it’s used to make recommendations to potential purchasers. I’ve also had authors reach out to me and ask me to write a review because I’ve rated their book.

I really want a rating system with many more subcategories. Readability, character development, plot, dialog, descriptions, … And each category of book might have an additional subset of categories. Nonfiction books might have an accuracy category. Science fiction books might have a universe category.

How do you choose to rate a book? Do you just pick a star rating based on how you feel? Or do you have a system? Who are you rating it for?